Home » OM 617 » OM 617 – Oil circuit, oil pressure, pressure relief valve and oil filter

OM 617 – Oil circuit, oil pressure, pressure relief valve and oil filter

Oil pressure
At operating temperature, the oil pressure at idle may drop to 0.5 bar gauge pressure (0.5 atij). During acceleration, the oil pressure should rise again immediately and should attain at least 3 bar gauge pressure (3 atu) at 3000/min.

Pressure relief valve
On engine 615, the pressure relief valve is screwed in or on, respectively, main oil duct at engine face and on engines 6161617 at oil pump.

If there is no oil pressure or if the oil pressure is too low, check whether oil pressure relief valve on oil pump has dropped or become loose.
In both cases, coat threads of oil pressure relief valve with sealing compound, part No. 002 989 94 71 and screw-in.

Bypass valve in oil filter
The bypass valve (1 1) opens when the difference in pressure between the dirty side and the clean side of filter exceeds 3.5 bar gauge pressure.
This will happen when the filter element is heavily contaminated. The oil will then flow to engine in uncleaned condition.

Oil filter
The main and bypass filter elements are separately located.
During first inspection (500-1000 km), replace initial operation filter element with filter cartridge ( 4 )
and main flow filter plate element (3).
Then replace filter cartridge during oil change every 5000 km.

Clean main flow filter plate element with holding pliers 1 10 589 00 68 00 in benzine.

Operation
Engines 615 and 616
Coming from feed duct (a), the oil flows into oil filter housing. The major portion of the oil flows through
main flow filter element (4) and via duct (b) into main oil duct and to the bearing points. The remaining oil flows from outside through bypass filter element (6) where i t is finely filtered and from there across a groove in hex. bolt (10) through throttle bore (d) back into oil pan.

Engine 616
Starting at a differential pressure of approx. 1.5-1.7 bar, the oil will flow directly to main and bypass filter element.
Below approx. 1.5-1.7 bar differential pressure, the bypass valve (1 1) will close. The oil will now flow via air oil cooler to main and bypass filter element.

Engine 617
Starting at an oil temperature of approx. 95C, thermostat ( 13) begins displacing control valve ( 1 2).
In end position, the direct flow to main or bypass filter element is closed except for a given quantity of
oiI.

This quantity of oil is enough to guarantee lubrication of engine a t low outside temperatures when the through-flow in oil cooler i s extensively prevented by the viscosity of the oil.

The major portion of the oil flows to air oil cooler and is cooled there, it will then flow back to oil filter housing and through main and bypass filter element to bearing points or oil pan.

When the filter element i s badly contaminated and the differential pressure between the dirty and the clean side of the filter exceeds 3.5 bar gauge pressure, the bypass valve ( 1 7) will open. The oil will then flow to engine in uncleaned condition.

B. Model 123.1

On engines 616.912, starting February 1979, on vehicles with air conditioning system, the air oil cooler
of version A has been replaced by version 0.
Air oil coolers of version B cannot be installed in vehicles with version A.

Air oil cooler and thermostat in oil filter
Engine with air oil cooler and thermostat in oil filter
61 5 only on vehicles with air conditioning system
616 standard up to June 1978, starting July 1978 on vehicles with air conditioning system only
6 17 general

Oil pressure
A t operating temperature, the oil pressure at idle may drop to 0.5 bar gauge pressure (atu).
During acceleration, the oil pressure should immediately rise again and attain at least 3 bar gauge pressure (atu) a t 3000lmin.
In the event of complaints about trembling of oil pressure gauge needle, the throttle pin, part No. 123
542 00 74 can be installed in pressure gauge line at instrument end with tip first.

Pressure relief valve on oil pump
The dampened oil pressure relief valve (7 bar gauge pressure) is screwed to oil pump.

At no or insufficient oil pressure, check whether oil pressure relief valve has dropped from oil pump or
has become loose.
In both cases, coat threads on oil pressure relief valve with sealing compound, part No. 002 989 94 71 and screw-i n.

Bypass valve in oil filter
The bypass valve (8) opens when the differential pressure between the dirty and the clean side of the
filter exceeds 3.5 bar.
This will happen when the filter element i s badly contaminated. The oil will then flow to engine in uncleaned condition.

8 By pass valve
a from oil pump
b to main oil duct

Oil filter
The main and bypass filter element are combined in a cartridge.
During the first insprection (500-1000 km), replace initial operation filter element (1) with combination filter element (2).

Then replace combination filter element during oil change every 5000 km.
Filter element (B), part No. 617 184 01 25 replaces filter element, part No. 61 7 184 00 25 and can be installed in all diesel engines with upright oil filter.
On the other hand, do not install filter element, part No. 61 7 184 00 25 in engine 617.950.

1 st version
Up to October 1976, the oil filter cover has been attached with a central bolt (1). The central bolt (1) is
simultaneously the return flow pipe for the fine-filtered engine oil.

The central bolt has no check valve.

When changing the filter element, loosen central bolt and pull out until the throttle bore (arrow) projects about 5 mm above housing cover. As a result, the return flow duct in filter housing lower half will no longer be closed by the central bolt and the engine oil can flow back into oil pan.

2nd version
Starting November 1976, the oil filter cover is attached by means of two nuts.
The return flow pipe (18) is pressed into cover and is provided with a check valve (19).
When changing the filter element, unscrew cover (3) and pull up for a given distance. As a result, the return flow pipe (18) on cover will free a bore which connects the ducts (b) and (c) with each other. The oil in oil filter will flow into oil pan through duct (c).

Operation
The oil filter comprises the following main components:
a) Oil filter housing with bypass valve, return flow locking valve and thermostat.
b) Cover with return flow pipe, check valve and sealing ring.
c) combination filter element.

Coming from feed duct (a), the oil flows through return flow locking valve (16 and 17) into oil filter housing and flows directly to combiantion filter element.

After flowing through combination filter element, the oil, which has been cleaned in main flow filter element (16a1, continues flowing through header pipe (22) and duct (b) to main oil duct and on to bearing points.

On the other hand, the oil, which has been fine-filtered in bypass filter section (16), flows through return pipe ( 18) and duct (c) to oil pan.
To keep the main flow and the bypass flow separate, a rubber seal is inserted in combiantion filter element.

Engine 617 and engines 615, 616 with air oil cooler
Starting at an oil temperature of approx. 95C, the thermostat (11) beginns displacing the control valve
(12), which will attain i t s end position at approx.
110c. In the end position, the direct flow to combination filter element is closed except for a given quantity of oil (g). This oil quantity is enough to guarantee lubrication of engine at low outside temperatures, when the through-flow in oil cooler i s considereably detained by the now viscous oil.
The major oil quantity arrives at air oil cooler where it is cooled and then flows back to oil filter housing and through oil filter housing from outside in.
The cleaned oil flows through header pipe (22) or return flow pipe ( 1 8) to bearing points or into oil pan.

If the filter element is badly contaminated and the differential pressure between the dirty and the clean
side of the filter exceeds 3.5 bar, the bypass valve (8 and 9) opens. The oil will then flow to engine in
uncleaned condition.

The return flow locking valve (16 and 17) and the check valve (19) in return flow pipe (18) prevent the oil from oil filter flowing back into oil pan when the engine is shut off for longer periods.

Complaints concerning oil filter
1. On oil filter 1st version, the oil may flow from oil filter housing back into oil pan after an extended pe-
riod of inoperation of engine. As a result, the following faults will occur:
a) Delayed indication of oil pressure by pressure gauge.
b) Oil level in engine too high.
Note: Replacement of oil filter because of these complaints is not justified, since in this connection any fears concerning subsequent bearing damage are unfounded. The lubrication of the bearing points is guaranteed by the residual oil in bearing points in spite of a delayed response of the oil pressure gauge.

2. If following a change of filter element an oil pressure (0.5 atii) is indicated at idle speed, observe the
following:

Excessive force when inserting central bolt ( 1) during a filter change may push the sealing ring (24) out of its hold into a position in front of header pipe (22).
The oil will then be supplied via the overflow valve (8) which will result in a drop in oil pressure. To avoid pushing out sealing ring (24),insert central bolt (1) into oil filter without using force.

Check pressing-in depth of riser pipe in oil filter.
Height of riser pipe from upper edge of pipe up to contact surface of filter element should not exceed
41 + 1 mm. If the height exceeds 42 mm, renew complete oil filter.

 

 

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